Stabilization of organic nitrates



' temperatures.

Patented Aug. 4, 1931 j "UiNtTE. s'rr RUSSELL MCGILL, OE WILMINGTON, DELAWARE, AASSIGNOR TO (I. DU IONT DE NEMOURS & COMPANY, OF WILMINGTON, DELAVIARE, A- GO B-PORATION 01E 'DELA- WARE STABILIZATION OF ORGANIC NITRATES No Drawing.

This invention relates to a process for stabilizing organic nitrates.

In the co-pending application of Dr. James H. Werntz there is described a method of v5 stabilizing organic nitrates by treating them with ethylene oxide. If the nitrate to be stabilized is a solid, this process is preferably carried out by dissolving it in a suitable solvent and treating it with ethylene oxide at temperatures at which ethylene oxide is a liquid. At temperatures at which ethylene oxide is a gas the treatment is carried out by bubbling the ethylene oxide through the nitrate. If the nitrate is a liquid, it is unnecessary to dissolve it. The use of ethylene oxide has the possible disadvantage that after the treatment the ethylene oxide, being gaseous at normal temperatures, will be volatilized and leave the organic nitrate. Should the organic nitrate subsequently be exposed to conditions which would tend to add or to generate unstabilizing decomposition proclucts, the stability of the compound would be affected.

It is an object of this invention to stabilize organic nitrates. Another object of this invention is to stabilize organic nitrates by substances which are non-volatile at ordinary temperatures.

These objects are accomplished by stabilizing the nitrate with compounds which contain the ethylene oxide grouping and which have boiling points so sufliciently high that they will remain in the nitrate at ordinary These objects are attained more particularly by the use of epichlorohydrin.

In the practice of my invention the nitrate to be stabilized, if solid, is preferably dissolved and treated with epichlorohydrin, although it may be treated with the epichlorohydrin without dissolving. After the treatment with epichlorohydrin the nitrate may be separated from the solution in any con- Application filed June 3, 1930. Serial No. 459,119.

venient way such as by precipitation with a.non-solvent, or hy distillation at lowtemperature and reduced pressure;

If the nitrateto be stabilizedis a liquid, the epichlorohydrinis simply-added thereto in :suflicient quantities :to attain the desired result.

Should it become desirable to stabilize a b above C.) the nitrate can be .bubbled through the epichlor ohydrin.

Should it'be desired to remove the stabilizing agent and the product of :its reaction 'aseous nitrate (for-instance, methyl nitrate with. theiunstabilizing.compound, this. can be Example I A- sample of glyceryltrinitrate, which had been washed several times with water and dried, was mixed with epichlo-rohydrin and its stability wasdetermined by the Abel test. This test consists in'heating a1 g. sample of a nitrate at"'.5 C. ina-test-tube with apiece of starch-potassium iodide paper which has been wetted with a solution consisting of equal :parts ofwater and glyce-rine. The appearance of a faint brown color on the paper indicates that the organic nitrateais'd-ecomposing. for the appearance of color is notedin-column two of .the following table. In col- The number of minutes required Column one Two Three Four Time for Time for appearance of Per cent appearance of color before epichlorocolor after treatment hydrin treatment minutes minutes Glyceryl trinitrate 35 1. 0 60+ Glyceryltrinitrate 35 5.0 60+ Glyceryl trinitrate 35 10. 0 60+ Example [1 Three grams of mannitol hexanitrate was dissolved in epichlorohydrin after which the epichlorohydrin was evaporated and the mannitol hexanitrate washed with water and dried. The stability before treatment, as determined by the Abel test, was four minutes and after treatment was fourteen minutes.

My invention is applicable to the stabilization of other nitrates than those mentioned in the above examples, in fact to all organic nitrates which contain or which may gen: erate, unstabilizing decomposition products which are capable of reacting with the ethylene oxide radical. Among these organic nitrates may be mentioned cellulose nitrate.

Among the advantages of my invention is the fact that the stabilizing compounds remain in the nitrate and thus prevent its unstabilization by the addition or generation of unstabilizing compounds.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that I do not limit myself to the specific embodiments thereof except as defined in the appended claims.

I claim:

1. The method of stabilizing organic nitrates comprising adding thereto a substance containing the ethylene oxide structure hav ing a boiling point so sufficiently high that it will remain in the compound.

2. The method of stabilizing organic nitrates comprising adding thereto a substance containing the ethylene oxide structure having a boiling point so sufficiently high that it will remain in the compound at ordinary temperatures.

3. The method of stabilizing organic nitrates comprising adding epichlorohydrin thereto.

4. The method of stabilizing organic ni- 

